Re: [PATCH net v2] net/mlx5e: strip runt Ethernet padding in HW-GRO (SHAMPO)
Tariq Toukan <[email protected]>
| Newsgroups | org.kernel.vger.linux-rdma,org.kernel.vger.linux-kernel,org.kernel.vger.netdev |
|---|---|
| Message-ID | <[email protected]> |
On 04/08/2026 0:44, Glenn Judd wrote:
> When hardware GRO (SHAMPO) coalesces a small IPv4/TCP segment
> that was padded up to the 60-byte minimum Ethernet frame, the trailing
> padding is folded into the merged payload.
>
> The selftest tools/testing/selftests/drivers/net/hw/gro.py subtest
> hw_ipv4_data_lrg_1byte sends {100, 1} expecting to receive {101}.
> In current code, it receives {106} (100 + 1 payload + 5 pad) instead.
>
> Fix is to compute the real (unpadded) frame length from the segment's
> IPv4 total (padded) length and drop the padding before it is merged.
>
> Fixes: 92552d3abd32 ("net/mlx5e: HW_GRO cqe handler implementation")
> Cc: [email protected]
> Assisted-by: Claude:claude-opus-4-8
> Assisted-by: Codex:gpt-5.6
> Assisted-by: Meta:internal-AI-tooling
> Signed-off-by: Glenn Judd <[email protected]>
> ---
>
> Notes:
> v2:
> - No functional change.
> - Address the netdev checkpatch 80-column warning.
> - Add a comment noting the IPv4 header offset intentionally mirrors the
> driver's existing no-IP-options logic (raised in review).
> Changing that logic is outside the scope of this change.
> v1: https://lore.kernel.org/netdev/[email protected]/
>
Hi,
Please note that I posted comments on v1, ~1h before your v2.